Although she was invariably known as the deadpan foil to husband and performing partner Louis Prima, singer Keely Smith needed nobody's help. Her casual insouciance made her a natural jazz swinger, full of sass and style. The crystalline elegance of her ballad singing on “Someone to Watch Over Me” proves her versatility, and on “It Had to Be You” she plays the ingénue with whispery effectiveness, spiking innocence with an undercurrent of cynicism.